LBHNC: A lunar‐based heavy nucleus detector

A passive, large‐area experiment for the detection of cosmic ray actinides on the lunar surface is discussed. Due to the absence of a geomagnetic cutoff, a 100 m2 array of nuclear‐track‐detecting glass plates in 5 years will detect ∼300–1000 U and Th cosmic ray nuclei of energies ≳0.85 GeV/u (compared to the present world’s total of 4 actinides). With a charge resolution at uranium of ∼0.25e, the U/Th ratio can be accurately determined, thereby dating the r‐process component of the cosmic rays; the presence of a fresh r‐process component would be corroborated by the likely detection of transuranics as well. In addition, abundances in the Pt/Pb and sub‐Pt/Pb regions and abundances of secondary actinides would provide detailed data on the 0–1 g/cm2 region of the cosmic ray path length distribution, hence on the astrophysical site of origin of these cosmic rays. Finally, should a fresh r‐process component exist, the dection of postulated suerheavy nuclei is conceivable. With an analysis station at the Lunar Base, glass plates could periodically be harvested, analyzed, annealed/remelted, and replaced onto the lunar surface.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87598/2/289_1.pd

Journaux et Internet: enjeu economique, enjeu democratique

Since 1995, along with the rise of the Internet, traditional daily papers have been experiencing a real revolution. There are three stakes in this game. The first is economic: how to ensure their survival, which is dependent on finances? The second is ethical: how to guarantee proven valuable information in the net? The third is political: how to ensure equal access to complete, reliable, and pluralistic information, which is the main pillar of democracy? This article offers an analysis of answers to those questions, contained in the newspapers of the Western democracies, particularly the American press

Sub-Pixel Response Measurement of Near-Infrared Sensors

Wide-field survey instruments are used to efficiently observe large regions of the sky. To achieve the necessary field of view, and to provide a higher signal-to-noise ratio for faint sources, many modern instruments are undersampled. However, precision photometry with undersampled imagers requires a detailed understanding of the sensitivity variations on a scale much smaller than a pixel. To address this, a near-infrared spot projection system has been developed to precisely characterize near-infrared focal plane arrays and to study the effect of sub-pixel non uniformity on precision photometry. Measurements of large format near-infrared detectors demonstrate the power of this system for understanding sub-pixel response.Comment: 9 pages, 13 figures, submitted to PAS

CONFLITOS NAS ÁREAS DE PRESERVAÇÃO PERMANENTE DA BACIA HIDROGRÁFICA DO CÓRREGO RICO, JABOTICABAL – SP

Os estudos de caracterização, diagnóstico e prognóstico de bacias hidrográficas visando o manejo dos recursos naturais têm sido realizados para compreender e implantar práticas de conservação no sistema produtivo agrícola. Este trabalho teve como objetivo caracterizar ambientalmente a Bacia Hidrográfica do Córrego Rico utilizando técnicas de geoprocessamento.  Nas áreas de preservação permanente foram identificadas as ocorrências de conflito de uso, tendo como referência a legislação ambiental. No que refere a sua degradação ambiental, vem ocorrendo uma diminuição na cobertura vegetal original nos mananciais, causada pelo desmatamento da mata ciliar decorrente da expansão da área urbana, e um abandono destas áreas na área agrícola. Em algumas regiões ocorreram reflorestamentos, tanto nas nascentes como ao longo da rede de drenagem. Do total de 34,51 km² relativos às áreas de preservação permanente, 6,16 km² (17,87%) estão sendo ocupados por mata, 8,40 km² (24,35%) ocupados pela cana em estágio inicial e 3,9391 km² (11,41%) cobertos por cana no estágio maduro. O trabalho permitiu obter um conjunto de informações georreferenciadas, possibilitando a caracterização ambiental da bacia hidrográfica para a tomada de decisão quanto à exploração do solo e as áreas prioritárias para a recomposição vegetal.Los estudios de la caracterización diagnóstico y pronóstico de cuencas, destinadas a la gestión de los recursos naturales se han realizado para entender e implementar prácticas de conservación en el sistema de producción agrícola. Este estudio tuvo como objetivo caracterizar el medio ambiente de la Cuenca Hidrográfica del Arroyo Rico utilizando técnicas de geoprocesamiento. En las áreas de preservación permanente se han identificado las ocurrencias de conflicto del uso, con referencia a la legislación ambiental. En referencia a su degradación medioambiental, se ha producido una disminución de la vegetación original en los mananciales, causada por la deforestación de la vegetación de ribera debido a la expansión de la zona urbana, y un abandono de estas áreas en las áreas agrícolas. En algunas regiones ocurrieran reforestaciones, tanto en las nacientes como al largo de la red de drenaje. Del total de 34,51 km² relacionados con las áreas de preservación permanente, 6,16 km² (17,87%) están siendo ocupados por los bosques, 8,40 km² (24,35%) ocupados por la caña de azúcar en una etapa temprana del ciclo y 3.939 km² (11,41%) cubierto por la caña de azúcar en etapa madura. El trabajo posibilitó la obtención de un conjunto de información geo-referenciadas, lo que permite la caracterización ambiental de la cuenca para la toma de decisión sobre el uso del suelo y las áreas prioritarias para la recuperación vegetal.The characterization, diagnosis and prognosis studies on watersheds aimed to manage the natural resource have been performed in order to understand and implement conservation practices of the agricultural production system. This study aimed to characterize the environment of the Córrego Rico watershed using geographic information system techniques. In the permanent preservation areas we identified areas of land use conflict, with reference to Brazilian environmental legislation. In terms of its environmental degradation, there has been a decrease of vegetation cover in the watershed caused by deforestation of riparian vegetation, due to the expansion of the urban area, and an abandonment of these areas was observed. In some regions, reforestation occurred in both the springs and along the drainage network. Of the total area, 6.12% are occupied with permanent preservation area, totalizing 34,51 km². Of these areas, 17,87% was occupied by forest, 24.35% was occupied by sugarcane at an early stage and 11.41% covered by sugarcane in the mature stage. The methodology yielded a set of georeferenced information, enabling the characterization of environmental watershed for decision making, regarding the exploitation of the soil and the priority areas for conservation management

New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV

We present a new measurement of the cosmic-ray positron fraction at energies between 5 and 15 GeV with the balloon-borne HEAT-pbar instrument in the spring of 2000. The data presented here are compatible with our previous measurements, obtained with a different instrument. The combined data from the three HEAT flights indicate a small positron flux of non-standard origin above 5 GeV. We compare the new measurement with earlier data obtained with the HEAT-e+- instrument, during the opposite epoch of the solar cycle, and conclude that our measurements do not support predictions of charge sign dependent solar modulation of the positron abundance at 5 GeV.Comment: accepted for publication in PR

Antiparticles

Nearly a half century after the discovery of the antiproton the study of cosmic-ray antimatter continues to be an exciting and fertile field. Sensitive searches for heavy cosmic-ray antimatter continue, although in recent years their value as a probe of universal baryon symmetry has all but evaporated. Antiprotons and positrons have opened new windows on the origin and history of cosmic rays. The rarity of antimatter as compared to ordinary cosmic-ray species has posed substantial experimental challenges. Early reports of significant enhancements of antiprotons and high-energy positrons fueled speculation that non-baryonic dark matter had been found. A new generation of balloon-borne magnetic spectrometers employing powerful particle identification techniques to eliminate background have finally managed to uncover the true antimatter signal. These new measurements support simple models of secondary production but also suggest the possibility of a small yet interesting primary component.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43807/1/11214_2004_Article_382988.pd

Calibration of Plastic Phoswich Detectors for Charged Particle Detection

The response of an array of plastic phoswich detectors to ions of $1\le Z\le 18$ has been measured from $E/A$=12 to 72 MeV. The detector response has been parameterized by a three parameter fit which includes both quenching and high energy delta-ray effects. The fits have a mean variation of $\le 4\%$ with respect to the data.Comment: 17 pages, 5 figure

Proposta metodológica de Pagamentos por Serviços Ambientais (PSA) visando a produção de água limpa em mananciais

The Payment for Environmental Services (PES) instrument aims to quantify an Ecosystem Service (ES), so that its production is valued and based on a socioeconomic financial system for conservation. The land use on the terrain and the environmental attributes of a watershed directly interfere in the capacity to store water in the system of a functional unit and can be transformed into an Environmental Service. The proposed methodology aims to determine environmental indicators that can support the valuation of the production of water of better quality. The environmental attributes of geology, soil, slope and land use land cover are measured and analyzed. The zoning of the most vulnerable rural areas was determined for possible implementation of PES programs and valuation of spring water in proportion to the contribution of their water production area in the sub-basin. The methodology has proven to be efficient in determining the most environmentally vulnerable areas, in order to classify water production by sub-basins, and it suggests a market form for financing ecosystem conservation that considers the principles of the provider-receiver (which contribute to the generation of environmental service –water and soil quality) and user-payer (who benefit from and pay for it). The financial incentive to rural producers in watershed areas is only provided when management and conservation practices are carried out through activities of plant and animal production on a sustainable land use.O instrumento de Pagamento por Serviço Ambiental (PSA) visa quantificar um Serviço Ecossistêmico (SE) de forma que sua produção seja valorada e baseada em um sistema financeiro socioeconômico da conservação. O uso do solo nas vertentes e os atributos ambientais de uma bacia hidrográfica interferem diretamente na capacidade de armazenar água no sistema de uma unidade funcional e podem ser transformados em Serviço Ambiental (SA). A metodologia proposta tem como objetivo determinar indicadores ambientais que possam dar suporte a valoração da produção de água de melhor qualidade. Os atributos ambientais geologia, solo, declividade e cobertura do solo são mensurados e analisados. O zoneamento das áreas rurais mais vulneráveis foi determinado para possível valoração da água de manancial de forma proporcional a contribuição da sua área de produção de água na sub-bacia e para a implementação dos programas de PSA. A metodologia se demonstrou eficiente para determinar as áreas mais vulneráveis ambientalmente, de forma a classificar as áreas ambientalmente mais vulneráveis e na produção de água por subbacias. O processo é passível de se tornar uma forma de mercado da água para financiamento da conservação do ecossistema que considera os princípios do provedor-recebedor (que contribuem para a geração do SA – água e solo de qualidade) e usuário-pagador (que se beneficiam e pagam o SA). O incentivo financeiro ao produtor rural de áreas de manancial deve ser realizado somente quando ocorrem práticas de manejo e conservação por meio de atividades de produção vegetal e animal de uso do solo sustentável